Preheat oven to 350°F. Line a rimmed baking sheet with aluminum foil.
Mix meatball ingredients with hands until just combined; beef, pork, bread crumbs, minced onion, 1 teaspoon garlic powder, salt, pepper, parsley flakes, sour cream, and eggs.
Roll meat mixture into 2-inch meatballs (about 30 golf ball sized). Transfer to the baking sheet.
Bake for 30-35 minutes or until meatballs are cooked through to 160°F internal temperature.
Combine all sauce ingredients in 3 qt pot over medium heat; apple butter, soy sauce, water, sugar, 1 teaspoon garlic powder, onion powder, and grated ginger.
Heat for 10 minutes while stirring occasionally. Once sauce begins to simmer, remove from heat.
Serve meatballs with sauce and optional fresh chives and sesame seeds.